1 files changed, 79 insertions, 3 deletions

diff --git a/block/blk-mq-cpumap.c b/block/blk-mq-cpumap.c
index 9638b25fd521..705da074ad6c 100644
--- a/block/blk-mq-cpumap.c
+++ b/block/blk-mq-cpumap.c
@@ -11,16 +11,57 @@
 #include <linux/smp.h>
 #include <linux/cpu.h>
 #include <linux/group_cpus.h>
+#include <linux/device/bus.h>
+#include <linux/sched/isolation.h>
 
 #include "blk.h"
 #include "blk-mq.h"
 
+static unsigned int blk_mq_num_queues(const struct cpumask *mask,
+				      unsigned int max_queues)
+{
+	unsigned int num;
+
+	num = cpumask_weight(mask);
+	return min_not_zero(num, max_queues);
+}
+
+/**
+ * blk_mq_num_possible_queues - Calc nr of queues for multiqueue devices
+ * @max_queues:	The maximum number of queues the hardware/driver
+ *		supports. If max_queues is 0, the argument is
+ *		ignored.
+ *
+ * Calculates the number of queues to be used for a multiqueue
+ * device based on the number of possible CPUs.
+ */
+unsigned int blk_mq_num_possible_queues(unsigned int max_queues)
+{
+	return blk_mq_num_queues(cpu_possible_mask, max_queues);
+}
+EXPORT_SYMBOL_GPL(blk_mq_num_possible_queues);
+
+/**
+ * blk_mq_num_online_queues - Calc nr of queues for multiqueue devices
+ * @max_queues:	The maximum number of queues the hardware/driver
+ *		supports. If max_queues is 0, the argument is
+ *		ignored.
+ *
+ * Calculates the number of queues to be used for a multiqueue
+ * device based on the number of online CPUs.
+ */
+unsigned int blk_mq_num_online_queues(unsigned int max_queues)
+{
+	return blk_mq_num_queues(cpu_online_mask, max_queues);
+}
+EXPORT_SYMBOL_GPL(blk_mq_num_online_queues);
+
 void blk_mq_map_queues(struct blk_mq_queue_map *qmap)
 {
 	const struct cpumask *masks;
-	unsigned int queue, cpu;
+	unsigned int queue, cpu, nr_masks;
 
-	masks = group_cpus_evenly(qmap->nr_queues);
+	masks = group_cpus_evenly(qmap->nr_queues, &nr_masks);
 	if (!masks) {
 		for_each_possible_cpu(cpu)
 			qmap->mq_map[cpu] = qmap->queue_offset;
@@ -28,7 +69,7 @@ void blk_mq_map_queues(struct blk_mq_queue_map *qmap)
 	}
 
 	for (queue = 0; queue < qmap->nr_queues; queue++) {
-		for_each_cpu(cpu, &masks[queue])
+		for_each_cpu(cpu, &masks[queue % nr_masks])
 			qmap->mq_map[cpu] = qmap->queue_offset + queue;
 	}
 	kfree(masks);
@@ -54,3 +95,38 @@ int blk_mq_hw_queue_to_node(struct blk_mq_queue_map *qmap, unsigned int index)
 
 	return NUMA_NO_NODE;
 }
+
+/**
+ * blk_mq_map_hw_queues - Create CPU to hardware queue mapping
+ * @qmap:	CPU to hardware queue map
+ * @dev:	The device to map queues
+ * @offset:	Queue offset to use for the device
+ *
+ * Create a CPU to hardware queue mapping in @qmap. The struct bus_type
+ * irq_get_affinity callback will be used to retrieve the affinity.
+ */
+void blk_mq_map_hw_queues(struct blk_mq_queue_map *qmap,
+			  struct device *dev, unsigned int offset)
+
+{
+	const struct cpumask *mask;
+	unsigned int queue, cpu;
+
+	if (!dev->bus->irq_get_affinity)
+		goto fallback;
+
+	for (queue = 0; queue < qmap->nr_queues; queue++) {
+		mask = dev->bus->irq_get_affinity(dev, queue + offset);
+		if (!mask)
+			goto fallback;
+
+		for_each_cpu(cpu, mask)
+			qmap->mq_map[cpu] = qmap->queue_offset + queue;
+	}
+
+	return;
+
+fallback:
+	blk_mq_map_queues(qmap);
+}
+EXPORT_SYMBOL_GPL(blk_mq_map_hw_queues);